Most persons have experienced the struggle and frustration of attempting to move a heavy container from place to place. With containers used outdoors, the problem is aggravated when the terrain over which the container is transported is uneven and/or yielding like sand.
Earlier workers in the field of container "transport" have attempted to make this task easier by providing wheels. U.S. Pat. No. 4,311,222 (Castanier) shows a suitcase having tiny wheels (or "rollers" as the patent calls them) mounted thereto for more easily transporting the suitcase in railway cars, railway stations or on a carpet, all of which are generally flat, firm surfaces. The rollers are oriented so that the suitcase can be "walked" along edgewise or towed by a handle. While this patent is not particularly clear in all of its descriptive detail, it is apparent that the rollers are mounted in a fixed position for suitcase transporting. If one wishes to remove a roller, the suitcase must be opened and the roller retaining beads squeeze together to permit the roller to be withdrawn from its holder.
U.S. Pat. No. 4,846,493 (Mason) shows a container embodied as a portable cooler with wheels mounted for pivoting movement between extended and retracted positions. Wheel extension and retraction is purely manual That is, when transporting the cooler using the wheels, a cross-rod is disengaged from an upper pair of hooks, pushed downward to extend the wheels and engaged with a lower set of hooks. When the user wishes to retract the wheels, the rod is disengaged from the lower hooks and re-engaged with the upper hooks. While the cooler has a front towing handle, wheel extension and retraction is unrelated to the handle or to handle movement.
These examples of earlier efforts in this field tend to have certain disadvantages. The suitcase rollers shown in the Castanier patent are extremely small and appear to be suitable for use only on a smooth surface. And such rollers are difficult to attach and remove. At least for removal, the suitcase must be opened.
While the wheel arrangement shown in the Mason patent is better adapted for uneven terrain and sand, it appears not to be especially handy to use. That is, to use the wheels, one must place the cooler on a surface, go to the cooler rear portion and unlatch and lower the wheels. Only then can the user take up the towing handle for cooler transport. When the cooler is to be carried in a vehicle for example, one must again place the cooler and manually retract the wheels using a procedure substantially the opposite of that described above.
A container having wheels automatically positioned by manipulation of the container handle would be an important advance in the art.